The present invention is an improvement on the low-cost, low-pressure, feedback passage-free oscillators disclosed in U.S. Pat. No. 5,213,269 and U.S. Pat. No. 5,213,270, owned by the assignee hereof. In these patents, a fluidic oscillator is disclosed which has an oscillation chamber having a length greater than its width and a pair of mutually facing complementary shaped sidewalls with planar top and bottom walls and first and second ends walls and is generally "box" shaped. An input power nozzle is formed in the first end wall for issuing a stream of liquid into the oscillation chamber, and an outlet is formed in the second end wall to issue a sweeping jet to ambient. Alternately pulsating substantially cavitation-free vortices are formed in the chamber. This defines a standard box fluidic oscillator. In U.S. Pat. No. 5,213,269, an interconnect passage or channel proximate the downstream end wall, enlarges the sweep angle and improves periodicity of the oscillations.
The present invention is an improvement on the fluidic oscillator disclosed in U.S. Pat. No. 5,213,269 by improving the patternization, frequency and quality of oscillations of the fluidic oscillator disclosed in U.S. Pat. No. 5,213,269. This has been done by incorporation of a transverse slot which connects the fluid from regions on opposite sides of the power jet a substantial distance downstream thereof and in advance of the outlet throat and orifice. In the preferred embodiment, the distance of the transverse slot from the output is from about the edge of the downstream end of the oscillation chamber to about 0.48L where L is the distance from the power nozzle to the outlet opening in the oscillation chamber. In this position, the transverse slot provides a method of controlling the patternization, the spray distribution across the fan angle of the output, the average frequency and the amount of time spent in steady predictable oscillations. This results in liquid oscillators which are less expensive to manufacture and produces a higher manufacturing yield. While rectilinear slots are disclosed, other slot shapes can be used.